Texas officials have charged a 17-year-old student with murder over the high school massacre where 10 people, including fellow pupils, were shot and killed.

Students said gunman Dimitrios Pagourtzis opened fire in a classroom at Santa Fe High School shortly before 8am CT (13.00 GMT) on Friday, and that they fled in panic after seeing classmates wounded while a fire alarm triggered a full evacuation.

It was the latest in a long series of deadly shootings at American schools.

Seventeen teens and educators were shot dead in Parkland, Florida, in February - a massacre that stirred the nation's long-running debate over gun ownership.

Police officials said Dimitrios Pagourtzis had been charged with capital murder in a post on Facebook (Image: REUTERS)

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The school has some 1,462 students, according to federal education data.

U.S. President Donald Trump called the latest school massacre "absolutely horrific."

"My administration is determined to do everything in our power to protect our students, secure our schools and to keep weapons out of the hands of those who pose a threat to themselves and to others," Trump said at the White House.

The jacket thought to have been worn by the shooter as he carried out his rampage

Days after the Parkland shooting, Trump said that elected officials should be ready to "fight" the powerful National Rifle Association lobby group.

But early this month he embraced that group, telling its annual meeting in Dallas "your Second Amendment rights are under siege."

The Second Amendment of the U.S. Constitution protects the right to bear arms.

The Born to Kill t-shirt displayed on the shooter's Facebook page

No major federal gun controls have been imposed since Parkland, though the administration is pursuing a proposed regulatory ban on "bump stocks," which enable a semi-automatic rifle to fire a steady stream of bullets.

The devices were used in an October 2017 mass shooting in Las Vegas that killed 59 people but have not played a role in other major U.S. mass shootings.